Kierkegaard vs. Descartes: The Ultimate Showdown

Kierkegaard’s most direct attack on Descartes’ cogito argument centers on what he identifies as a fundamental logical flaw: the presupposition of the very thing being proven. Kierkegaard argues that the cogito already presupposes the existence of the “I” as the thinking subject, making the conclusion of existence logically trivial1. This critique exposes a circular reasoning at the heart of Cartesian doubt.

The Danish philosopher clarifies this criticism by restructuring Descartes’ argument to reveal its hidden premises:

• “x” thinks

• I am that “x”

• Therefore I think

• Therefore I am

By this reformulation, Kierkegaard demonstrates that the “I” is already assumed in the initial premise, rendering the conclusion mere tautology1. For Kierkegaard, Descartes is simply “developing the content of a concept” – namely that the “I,” which already exists, thinks1.

Logical Triviality vs. Psychological Appeal

Kierkegaard distinguishes between the logical structure of Descartes’ argument and its psychological force. He argues that the value of the cogito is not in its logical validity but in its psychological appeal – the intuitive difficulty of thinking “I do not exist”1. This distinction is crucial to understanding why the cogito has been so persuasive despite its logical shortcomings.

According to Kierkegaard, “existence is already assumed or presupposed in order for thinking to occur, not that existence is concluded from that thinking”1. This reverses Descartes’ causal relationship, suggesting that existence is a precondition for thought rather than a conclusion derived from it.

The phrase “De omnibus dubitandum est” (Everything must be doubted) encapsulates Kierkegaard’s satirical approach to Cartesian doubt1. Through his pseudonym Johannes Climacus, Kierkegaard explores the existential consequences of taking methodic doubt to its ultimate conclusions2.

In his unfinished essay “Johannes Climacus, or De omnibus dubitandum est,” Kierkegaard portrays a young man who attempts to apply the principle of radical doubt throughout his life, ultimately reducing it to absurdity1. This work serves as a direct challenge to the philosophical absolutism of Cartesian skepticism and its methodological universalism3.

Doubt as Prefiguration of Existential Despair

One of Kierkegaard’s most profound insights is his characterization of Cartesian doubt as a “prefiguration of existential despair”34. Unlike Descartes, who saw doubt as a methodological tool for reaching certainty, Kierkegaard recognizes doubt as having deeper existential implications.

For the first time in Kierkegaard’s writings, this work confronts “the sphere of speculation (thinking)” with “personal involvement (will)”3. This distinction highlights Kierkegaard’s concern that Cartesian philosophy privileges abstract thought over existential commitment, neglecting the whole person in favor of disembodied reason.

Kierkegaard redirects philosophical thinking “toward the transcendent with all the limitations of human thought” and removes reason “from its once dominant place over cosmic reality”1. This represents a fundamental break from Descartes’ confidence in reason’s ability to establish certainty.

In “Philosophical Fragments,” published under the Climacus pseudonym, Kierkegaard further develops these themes, arguing that our historical knowledge of transcendence or the eternal is limited by the finitude of human thought1. However, he maintains that our concept of transcendence, “although negatively presented to our thought, signifies the reality of the concept”1.

Faith as Alternative to Reason’s Limits

While Kierkegaard challenges Descartes’ methodical doubt, he does not abandon the quest for certainty altogether. Instead, he presents faith as an alternative to “the problem of reason’s finite thinking”1. Unlike Descartes, who sought certainty through rational reflection, Kierkegaard suggests that certainty can only be approached through faith – a distinct mode of relating to truth that transcends the limitations of reason.

Concerning what he calls the “absolute paradox,” Kierkegaard writes: “The absurd, the paradox, is composed in such a way that reason has no power at all to dissolve it in nonsense and prove that it is nonsense; no, it is a symbol, a riddle, a compounded riddle about which reason must say…”1. This incomplete quotation nevertheless indicates Kierkegaard’s position that some truths lie beyond reason’s grasp.

Another significant aspect of Kierkegaard’s critique emerges in his rejection of mediation – the supposed connection between transcendence and immanence that was central to Hegelian philosophy1. Although Kierkegaard’s critique was not primarily directed at Descartes on this point, it reflects his broader concern with the limitations of rationalist approaches to knowledge.

Through his critique of mediation, Kierkegaard challenges the assumption that human reason can bridge the gap between finite human thought and infinite divine reality. This further undermines the Cartesian project of establishing certainty through methodical doubt and rational reflection1.

Kierkegaard’s critique of Descartes represents a profound challenge to the foundations of modern philosophy. By identifying the logical triviality of the cogito, the presupposition of the “I,” and the limitations of methodical doubt, Kierkegaard questions the very possibility of establishing certainty through reason alone.

The key phrases in Kierkegaard’s critique – “De omnibus dubitandum est,” the presupposition of the “I,” doubt as prefiguration of despair, and the limitations of human thought – reveal a thinker deeply concerned with the existential implications of philosophical methods. In contrast to Descartes’ confidence in reason, Kierkegaard emphasizes its limitations and points toward faith as an alternative mode of relating to truth.

This critique remains relevant today, challenging us to consider whether certainty can be established through rational reflection alone or whether some truths might require other modes of understanding that acknowledge the full complexity of human existence.